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#! /usr/bin/env python
"""Conversions to/from base64 transport encoding as per RFC-1521."""
# Modified 04-Oct-95 by Jack to use binascii module
import binascii
__all__ = ["encode","decode","encodestring","decodestring"]
MAXLINESIZE = 76 # Excluding the CRLF
MAXBINSIZE = (MAXLINESIZE//4)*3
def encode(input, output):
"""Encode a file."""
while 1:
s = input.read(MAXBINSIZE)
if not s: break
while len(s) < MAXBINSIZE:
ns = input.read(MAXBINSIZE-len(s))
if not ns: break
s = s + ns
line = binascii.b2a_base64(s)
output.write(line)
def decode(input, output):
"""Decode a file."""
while 1:
line = input.readline()
if not line: break
s = binascii.a2b_base64(line)
output.write(s)
def encodestring(s):
"""Encode a string."""
pieces = []
for i in range(0, len(s), MAXBINSIZE):
chunk = s[i : i + MAXBINSIZE]
pieces.append(binascii.b2a_base64(chunk))
return "".join(pieces)
def decodestring(s):
"""Decode a string."""
return binascii.a2b_base64(s)
def test():
"""Small test program"""
import sys, getopt
try:
opts, args = getopt.getopt(sys.argv[1:], 'deut')
except getopt.error, msg:
sys.stdout = sys.stderr
print msg
print """usage: %s [-d|-e|-u|-t] [file|-]
-d, -u: decode
-e: encode (default)
-t: encode and decode string 'Aladdin:open sesame'"""%sys.argv[0]
sys.exit(2)
func = encode
for o, a in opts:
if o == '-e': func = encode
if o == '-d': func = decode
if o == '-u': func = decode
if o == '-t': test1(); return
if args and args[0] != '-':
func(open(args[0], 'rb'), sys.stdout)
else:
func(sys.stdin, sys.stdout)
def test1():
s0 = "Aladdin:open sesame"
s1 = encodestring(s0)
s2 = decodestring(s1)
print s0, `s1`, s2
if __name__ == '__main__':
test()
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